1. Field of the Invention
This invention generally relates to a cable operating mechanism. More specifically, the present invention relates to a cable operating mechanism for a cable operated bicycle device with an operating lever that pulls and/or releases a greater amount of a control wire relative to an amount of angular displacement of the operating lever.
2. Background Information
Bicycling is becoming an increasingly more popular form of recreation as well as a means of transportation. Moreover, bicycling has become a very popular competitive sport for both amateurs and professionals. Whether the bicycle is used for recreation, transportation or competition, the bicycle industry is constantly improving the various components of the bicycle.
One part of the bicycle that has been extensively redesigned is the bicycle transmission. Specifically, a bicycle transmission typically includes front and rear shift operating devices designed to operate front and rear derailleurs to move the derailleurs laterally over a plurality of sprockets or gears. The sprockets or gears are usually coupled to the front crank and the rear wheel such that a pedaling force from the rider is transferred to the rear wheel via the chain.
Generally speaking, a typical derailleur basically includes a base member, a pair of link members and a movable member with a chain guide. In the case of a rear derailleur, the chain guide is typically pivotally mounted to the movable member and includes a chain cage with a guide pulley and a tension pulley. In either case, the link members of the front or rear derailleur are pivotally coupled between the base member and the movable member to form a four bar parallelogram linkage. A shift cable is usually coupled between the base member and one of the link members to move the chain guide laterally with respect to the center plane of the bicycle. Thus, an inner wire of the cable is pulled to move the chain guide in a first lateral direction with respect to the center plane of the bicycle, and released to move the chain guide in a second lateral direction with respect to the center plane of the bicycle.
Some cable operated shifters use one or more levers to rotate a wire takeup member for winding and releasing the inner wire that operates the derailleur. In many cases, the inner wire is wrapped or unwrapped about a peripheral edge of the wire takeup member. In such cases, during a winding or pulling operation, the winder lever is rotated to rotate the wire takeup member. Usually, the amount of angular displacement of the wire takeup member is nearly equally to the amount of angular displacement of the winder lever. Thus, in order to operate the derailleur, the rider may be required to rotate the winder lever a larger amount in order to pull the inner wire of the shift cable for the required amount to perform and complete a shift operation.
In view of the above, there exists a need for a bicycle shift operating device which overcomes the above mentioned problems in the prior art. This invention addresses this need in the art as well as other needs, which will become apparent to those skilled in the art from this disclosure.